intel: make bo_unreference() thread safe

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index 1e2dd77..bf6745d 100644 (file)
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -1157,7 +1157,8 @@ static void drm_intel_gem_bo_unreference(drm_intel_bo *bo)
        drm_intel_bo_gem *bo_gem = (drm_intel_bo_gem *) bo;
 
        assert(atomic_read(&bo_gem->refcount) > 0);
-       if (atomic_dec_and_test(&bo_gem->refcount)) {
+
+       if (atomic_add_unless(&bo_gem->refcount, -1, 1)) {
                drm_intel_bufmgr_gem *bufmgr_gem =
                    (drm_intel_bufmgr_gem *) bo->bufmgr;
                struct timespec time;
@@ -1165,8 +1166,12 @@ static void drm_intel_gem_bo_unreference(drm_intel_bo *bo)
                clock_gettime(CLOCK_MONOTONIC, &time);
 
                pthread_mutex_lock(&bufmgr_gem->lock);
-               drm_intel_gem_bo_unreference_final(bo, time.tv_sec);
-               drm_intel_gem_cleanup_bo_cache(bufmgr_gem, time.tv_sec);
+
+               if (atomic_dec_and_test(&bo_gem->refcount)) {
+                       drm_intel_gem_bo_unreference_final(bo, time.tv_sec);
+                       drm_intel_gem_cleanup_bo_cache(bufmgr_gem, time.tv_sec);
+               }
+
                pthread_mutex_unlock(&bufmgr_gem->lock);
        }
 }